1. Field of the Invention
The present invention relates to the field of laparoscopic or endoscopic instrumentation and surgery, and more particularly to a handle mechanism of an instrument for manipulating a surgical tool carried on the instrument.
2. Discussion of the Prior Art
A surgeon, when performing an operation on a patient, is often obstructed in his efforts to excise diseased or damaged tissues and organs by surrounding tissues or other organs. Retractor mechanisms have typically been utilized during surgery to retract and retain organs and tissues to clear the surgical site to allow access for the surgeon. In the past, it has generally been the case, when performing gastro intestinal surgery, i.e. surgery within the abdominal cavity, to make a large cut in the abdomen wall to produce a suitable opening to allow access to the interior organs. This cut was generally large enough to allow the use of human hands, either those of the surgeon or those of a member of the surgical team, as a retractor. Surgical personnel would thus be required to insert their hands or a retractor tool member through the incision into the abdominal cavity to push and hold organs and obstructing tissue away from the surgical objective.
Recently, as a result of developments in endoscopic and laparoscopic surgery, instruments have become smaller and are constructed with greater precision. In these procedures, small incisions are made through the surface of the skin in the vicinity of the surgical objective by trocar assemblies which provide a path to the surgical site. Through these incisions, miniaturized surgical instruments such as scissors, forceps, clamps, retractors, video equipment and scalpels may be inserted to perform various surgical procedures. The retractors provide a means for pushing tissue and organs which obstruct the surgical objective, to allow the surgeon access to surgical site.
While endoscopic instruments such as retractors are known in the art, many are operable only between a fully deployed position and a fully retracted position. Those that do provide for controlled opening do so with handle mechanisms which are difficult to operate and require greater dexterity on the part of the surgeon, than the use of other instruments.
Accordingly, a need exists for an endoscopic or laparoscopic retractor mechanism which allows for controlled opening and closing of the blades of the retractor, while the operation of the device is smooth and easy to manipulate. The present invention provides such a device.